Existing implantable medical leads for use with implantable pulse generators, such as neurostimulator, pacemakers, defibrillators or implantable cardioverter defibrillators (“ICD”), are prone to heating and induced current when placed in the strong magnetic (static, gradient and RF) fields of a magnetic resonance imaging (“MRI”) machine. The heating and induced current are the result of the lead acting like an antenna in the magnetic fields generated during an MRI. Heating and induced current in the lead may result in deterioration of stimulation thresholds or, in the context of a cardiac lead, even increase the risk of cardiac tissue damage and perforation. Moreover, induced currents may cause erroneous pacing or even fibrillation.
Over fifty percent of patients with an implantable pulse generator and implanted lead require, or can benefit from, an MRI in the diagnosis or treatment of a medical condition. MRI modality allows for flow visualization, characterization of vulnerable plaque, non-invasive angiography, assessment of ischemia and tissue perfusion, and a host of other applications. The diagnosis and treatment options enhanced by MRI are only going to grow over time. For example, MRI has been proposed as a visualization mechanism for lead implantation procedures.
There is a need in the art for an implantable medical lead configured for improved MRI safety. There is also a need in the art for methods of using such a lead.